[Immunopathology of diffuse malignant mesothelioma].

A so-called diffuse biphasic pleural and a monophasic malignant "fibrous" peritoneal mesothelioma were examined using monoclonal anticytoskeleton-antibodies and polyclonal antibodies against macrophage markers. Cytokeratin, vimentin and desmin were each expressed in both of the tumors. GFAP could not be detected. In addition the tumor cells differed in the quantity of macrophage markers. The immunologic findings corresponded to the histologic features of particular areas of the carcinosarcoma. This supports the view that malignant mesotheliomas derive from pluripotential mesothelial cells capable of both epithelial and mesenchymal differentiation. Contrary to some opinions expressed in the literature this histogenesis applies equally to the so-called monophasic diffuse "fibrous" mesotheliomas.